Air control



May 12, 1942. c. M. I 'ULLER 2,283,052

AIR CONTROL Filed May 6, 1940 2 Sheets-Sheet l INVENTOR Che-$5.114. Fuller ATTORNEYS Patented May 12, 1942 i i uNirEo AIR CONTROL Charles M. Fuller, Lodi, Calif., assignor to E. D. Wilkinson, Stockton, Calif.

Application May 6, 1940, Serial No. 333,453.

2 Claims. (Cl. 230-114) This invention relates to a dry concentrator of that type in which the concentration is effected with the aid of alternately applied air suction and pressure acting on the under side of a foraminous rifiie table. The concentrator to which this invention is particularly applied is that shown in my Patent No. 2,148,068 dated February 21, 1939, and the air control which is the subject of this invention is an improvement over that of the above patent.

When concentrating values from different materials, it is sometimes necessary, to obtain the best results, that the vacuum shall be increased, while the positive pressure is not changed, or may even be reduced. It is also sometimes necessary to alter the number of pulsations (alternate vacuum and pressure impulses) per minute without changing the vacuum or pressure.

It is therefore the principal object of this invention to provide an air control system for the purpose by means of which the above described independent alteration in pressure and suction or in the number of pulsations, may be easily efiected without changing the speed of the pressure blower and suction fan.

Another object is to provide an automatically functioning means to maintain constant, any predetermined pressure for which the system has been set, regardless of conditions on the tables tending to affect and alter such pressure.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a side elevation of the control apparatus, partly in section and with the concentrating tables omitted.

Figure 2 is a cross section on line 2-2 of Fig. 1, shown in connection with the tables.

Figure 3 is an enlarged fragmentary cross section on line 33 of Fig. 1.

Referring now more particularly to the char are passages 2 covered by tensioned fabric strips 3 or the like, rifile elements 4 projecting up from the fabric in the spaces between the passages. Each tunnel at its upper end is secured on and communicates with a valve housing 5. At the top, the housing communicates with a suction conduit 6 and at the bottom with a pressure or compression conduit 1. A rotary valve 8 is turnable in the housing and is divided into two chambers, one chamber being ported as at 9 to communicate with the tunnel and with conduit 6 while the other chamber is ported as at I!) to communicate with the tunnel and with conduit 1.

The valve ports arearranged relative tothe direction of rotation of the valve so that suction or vacuum communication with the tunnel is established the instant compression or pressure is shut oif, and regardless of the speed of rotation of the valve. All the valves of the concentrator are connected by a common shaft H which is driven by a variable speed motor l2, so that the number of rotations of the valve, and consequently the number of successive vacuum and pressure pulsations imparted to the rifile table at the fabric strips '3 may be varied from a minimum of R. P. M. to a maximum of 230 R. P. M.

The suction or vacuum conduit 6, which is common to all the valves, is connected at one end to a suction fan I 3. The opposite end of the conduit is provided with ports l4 normally closed by a closure plate [5 inside the conduit. The plate is mounted on a stem l6 slidable in a sleeve I! on the conduit. A spring l8 about the stem acts to hold the plate closed, the effectiveness of the spring being controlled by a finger nut [9 on the stem.

By reason of this arrangement, it will be seen that the fan l3, running at a constant speed, will create a tendency to vacuum in the tunnel I,

which will be constant and whose degree will depend-on the tension of the spring l8. If a heavier vacuum is desired, the spring is tightened by advancing the nut I9, and vice versa.

Similarly, the presure in conduit 1 will be automatically held constant at any adjustable degree desired irrespective of the vacuum. This is accomplished by the following means:

The conduit 1 is closed atone end and at the other end is connected to a driven blower which includes a housing 20 having a normally open intake 2| on one side and a plurality of auxiliary intake orifices 22 on the opposite side arranged about the axis of the blower. These orifices are normally entirely or partly open or closed by a shutter plate 23 turnably mounted on the housing axially of the blower and having orifices 24 to register with orifices 22. The plate is connected to an upstanding link 25 which at its upper end is connected to one end of an arm 26 extending transversely of and above the housing adjacent its junction with passage 1 and pivoted at its opposite end as at 21 on said housing.

The top of the housing under the arm is provided with an opening 28 covered on its under side by a flexible rubber sheet or diaphragm 29. This sheet is secured on an upstanding plunger 30 slidable in a guide member 3| on the housing.

A stem 32 on the plunger engages a vertically adjustable screw 33 mounted in and depending from arm 26 intermediate its ends. A weight 34 is mounted on the arm for adjustment lengthwise thereof between said screw 33 and the link 25.

By reason of this arrangement, it will be seen. that pressure in the housing will tend to force the plunger up, the pressure being resisted to any desired degree by the weight 34, so that a given pressure may be maintained in the housing. This is because any variation in pressure in the housing from a predetermined amount will cause the plunger and arm 26 to be moved, turning the shutter and altering the relative opening or closing of the orifices 22 to admit more or less air to the housing as the case may be.

The normal position of the shutter platei relative to orifices 22 is controlled by the adjustment of screw 33, which of course acts to raise or lower the link 25 and turn the shutter plate, without any corresponding movement of the plunger.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

the conduit is connected, the housing having an auxiliary intake opening, a movable closure shutter for said opening, a movable diaphragm exposed to pressure within the housing adjacent the conduit, a guided stem projecting from the diaphragm at right angles thereto, an arm extending over the stem and having an element intermediate its ends contacting with the stem, a pivot mounting for one end of the arm, a link connecting the other end of the arm and the shutter to move the latter with movement of the arm about its pivot, and means applied to the arm to provide a yieldable resistanceto the movement of the same by pressure against the housing side of the diaphragm.

2. A device as in claim 1 in which said element comprises an adjustable screw mounted in the arm axially of the stem.

CHARLES M. FULLER. 

